New possibilities for diver's monitoring during underwater diving using noises associated with natural respiration

Under normal conditions, breathing is reflexive, so it provides the necessary content of oxygen and carbon dioxide to the human body. However, elevated levels of partial oxygen, carbon dioxide and nitrogen pressure during underwater diving (considering the depth of diving, physical activity load, respiratory delays and changes in the inhaled gas density), require a conscious breathing control from the diver. Loss of breathing control can cause panic and/or loss of consciousness under water. The purpose of the paper is to study the possibility to control diver's physiological state under water by in-situ breathing noises. Materials and Methods. The authors developed a method to record underwater breathing noises of a scuba diver. The method ensures the determination of the breathing rhythm without violating the integrity of the respiratory apparatus tract. They also proposed a method to separate the inspiration and expiration sounds, which allowed them to control the duration of respiratory phase ratio...